[001] The present subject matter described herein, relates to a vehicle construction and more particularly, relates to a front portion structure of a vehicle.
BACKGROUND AND PRIOR ART:
[002] In front portion structures of passenger cars, bending of hood lock cross-member (or member) and radiator upper cross-member is a prominent phenomenon around 150Hz. This phenomenon is mainly due to coupling of natural frequencies of radiator upper cross-member and hood lock member. Both the radiator upper cross-member and hood lock member have their natural frequency around 150 Hz. Further in conventional designs, the connection of the radiator upper cross member is with the side brace lamp support member. This causes the bending of brace lamp support member, and because of this, the engine mount assembly incurs a translation mode. In conventional designs, the radiator upper cross-member is a part of two-pillar front-end design, being added to those vehicles where height of upper front end is more. The radiator upper cross-member serves the purpose of radiator supporting member. In conventional design, radiator upper cross-member is spot-welded to the side lamp brace members.
[003] Further, tactile vibrations occur in low frequency range - 100 Hz to 200 Hz. Major reason for the tactile vibration is the low dynamic stiffness of the sensitive paths of vibration transfer. One of the sensitive paths for vibration transfer is the engine mount attachment point. The root cause for low dynamic stiffness in the engine mounts is the resonance of front end structure, i.e. coupling of natural frequencies of radiator upper cross-member and hood lock member explained earlier. Such tactile vibrations are undesirable, and decoupling of the natural frequencies of radiator upper cross-member and hood lock member is required.

[004] Conventional methods of reducing the aforesaid tactical vibrations include - increasing the thickness of panels / components near engine mount, and / or addition of mass damper at engine mount location or radiator upper cross-member location. A mass damper is a block of steel with vibration dampening properties. However, such methods are cost inclusive, increase weight of the vehicle, decrease fuel efficiency, and reduce overall effectiveness of the vehicle.
[005] Japanese Patent publication JP2009126381 provides car body front part structure for automobile. The problem focus of the Japanese prior art includes -To reduce the vibration level of a cabin floor when the engine is idling by modifying the structure of a car body front part. The solution to the aforementioned problem provided - The car body front part structure is provided with a radiator support upper 1, a bumper reinforcement 3, and a radiator support lower 2, respectively arranged in the car width direction at an upper edge, a vertical center position, and a lower edge of a front end part of an engine room. It is also provided with a center brace 4 to support a car width center part of the radiator support upper 1 from the underside. The center brace 4 is coupled to the bumper reinforcement 3 at a lower end 42, while it is left uncoupled to the radiator support lower 2. When the engine is idling, it prevents resonance of the radiator support lower 2 due to vibration transmitted through a front side member 5 to the radiator support lower 2. It thus reduces the vibration level of the cabin floor.
[006] The Japanese prior art provides a center brace for preventing resonance of the radiator support lower. Hence, the structural and / or functional aspect of the solution provided by the prior art is different from the present disclosure. Moreover, the prior art solution includes a complex design and geometry, wherein provision of a center brace would require alteration of various components of front portion of vehicle, thereby increasing cost and ineffectiveness.

OBJECTS OF THE INVENTION:
[007] The principal objective of the present invention is to provide a front portion structure of a vehicle, wherein decoupling of natural frequencies of different components is achieved for reducing tactile vibrations.
[008] Another object of the present subject matter is to provide a simple, cost effective, and efficiently designed front portion structure of the vehicle that is distinct from all conventional designs.
SUMMARY OF THE INVENTION:
[009] The present invention relates to a front portion structure of a vehicle. The front portion structure includes a frame, which includes a hood lock member, two lateral vertical side members, and a lower cross member; and a U-shaped radiator upper cross member for supporting radiator of the vehicle, the U-shaped radiator upper cross member coupled to an underside of the hood lock member, wherein, the U-shaped radiator upper cross member defines a plurality of arcuate portions configured to be secured to the underside of the hood lock member, and an intermediate portion provided substantially between the plurality of arcuate portions, the intermediate portion being extending substantially in a forward or a backward direction of the vehicle.
[0010] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number

identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0012] Fig. 1 illustrates a conventional vehicle front chassis portion;
[0013] Fig. 2a illustrates a conventional frame of the front chassis portion of Fig.
i;
[0014] Fig. 2b illustrates a conventional radiator upper cross member of the conventional frame of Fig. 2a;
[0015] Fig. 3 illustrates a front portion structure of a vehicle according to an embodiment of the present disclosure;
[0016] Fig. 4a illustrates a U-shaped radiator upper cross member of the front portion structure of Fig. 3 in accordance with an embodiment of the present disclosure;
[0017] Fig. 4b illustrates an enlarged view of a portion of the U-shaped radiator upper cross member of Fig. 4a;
[0018] Fig. 5 illustrates a graph pertaining to vibration performance of a engine mount portion;
[0019] Fig. 6 illustrates a graph pertaining to tactile vibrations transferred to a floor of the vehicle from the engine mount portion; and
[0020] Fig. 7 illustrates a graph pertaining to drive-point frequency response function (FRF) comparison between the front chassis portion of Fig. 1 and the front portion structure of Fig. 3.
[0021] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and

methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0022] The present disclosure presents embodiments for a front portion structure of a vehicle. The front portion structure includes a frame, which includes a hood lock member, two lateral vertical side members, and a lower cross member; and a U-shaped radiator upper cross member for supporting radiator of the vehicle, the U-shaped radiator upper cross member coupled to an underside of the hood lock member, wherein, the U-shaped radiator upper cross member defines a plurality of arcuate portions configured to be secured to the underside of the hood lock member, and an intermediate portion provided substantially between the plurality of arcuate portions, the intermediate portion being extending substantially in a forward or a backward direction of the vehicle.
[0023] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

[0024] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0025] Fig. 1 illustrates a conventional vehicle front chassis portion 100. The front chassis portion 100 defining an engine mount portion 102, a conventional frame 104 having a hood lock portion 106 supported on a plurality of side lamp brace members 108 coupled to a lower portion 110. The conventional vehicle front chassis portion 100 further includes a conventional radiator upper cross member 112 coupled to the plurality of side lamp brace members 108.
[0026] Fig. 2a illustrates the conventional frame 104 of the front chassis portion 100. As can be seen, the conventional radiator upper cross member 112, being coupled to the plurality of side lamp brace members 108, defines a length L substantially similar to a length L' of the hood lock portion 106. Fig. 2b illustrates the conventional radiator upper cross member 112. As is understood from the background section, the conventional radiator upper cross member 112 being coupled to the plurality of side lamp brace members 108, includes low dynamic stiffness, and is thereby a sensitive path for transfer of tactile vibrations from the engine mount portion 102 towards floor of vehicle. The conventional design includes a bracket connected at the center of the radiator upper cross member 112. Further, design of the conventional frame 104 is prone to resonate due to coupling of natural frequencies of the hood lock portion 106, the plurality of side lamp brace members 108, and the conventional radiator upper cross member 112 in low frequency range - 100 Hz to 200 Hz, and further making the conventional radiator upper cross member 112 susceptible to high bending forces BF adjacent to the bracket.
[0027] Fig. 3 illustrates a front portion structure 300 of a vehicle according to an embodiment of the present disclosure. The front portion structure 300 includes a

frame 302. The frame 302 which includes a hood lock member 304, two lateral vertical side members 306, and a lower cross member 308. The front portion structure 300 further includes a U-shaped radiator upper cross member 310 for supporting a radiator (not shown) of the vehicle. In an embodiment, the U-shaped radiator upper cross member 310 is coupled to an underside of the hood lock member 304.
[0028] Fig. 4a illustrates the U-shaped radiator upper cross member 310 in accordance with an embodiment of the present disclosure. In an embodiment, the U-shaped radiator upper cross member 310 defines a plurality of arcuate portions 312. The plurality of arcuate portions 312 are configured to be secured to the underside of the hood lock member 304. In an example, the plurality of arcuate portions 312 may be secured to the underside of the hood lock member 304 by welding, for example, spot welding. Alternatively, any joining technique may be employed as know to a person skilled in the art. Further, a length LI of the U-shaped radiator upper cross member 310 is less than length L2 of the hood lock member 304. In an embodiment, a bracket 316 is provided between the hood lock member 304 and the intermediate portion 314 of the U-shaped radiator upper cross member 310.
[0029] Fig. 4b illustrates an enlarged view of a portion 400 of the U-shaped radiator upper cross member 310. As illustrated, the U-shaped radiator upper cross member 310 further includes an intermediate portion 314. In an embodiment, the intermediate portion 314 is provided substantially between the plurality of arcuate portions 312. As seen, the intermediate portion 314 of the U-shaped radiator upper cross member 310 extends substantially in a forward direction F of the vehicle. Alternatively, the intermediate portion 314 of the U-shaped radiator upper cross member 310 may extend substantially in a backward direction B of the vehicle. Since, the intermediate portion 314 of U-shaped radiator upper cross member 310 is either extended in the forward F or the backward B direction of the vehicle, the bracket 316 is connected at the edge of the intermediate portion 314 both in the forward F or the backward B direction as compared to the conventional design

where the bracket is connected at the center of the radiator upper cross member 112.
[0030] With continued reference to Figs. 1-4b, difference between the constructional and structural features of the conventional frame 104 and the frame 5 302 can be easily derived. Further, construction, structure, and mounting of the U-shaped radiator upper cross member 310 is different from the conventional radiator upper cross member 112. As the U-shaped radiator upper cross member 310 is coupled with the hood lock member 304, and not with the two lateral vertical side members 306 as against the prior art design, a decoupling of natural
10 frequencies of the U-shaped radiator upper cross member 310 and the hood lock member 304 in the low frequency range of 100 – 200 Hz is achieved. Such decoupling further ensures that minimal tactile vibrations are transferred from the engine mount portion 102 towards the floor of the vehicle. Since, the bracket 316 is connected at the edge of the intermediate portion 314 in either the forward F or
15 the backward B direction, the bending forces BF prevalent in the conventional radiator upper cross member 112 are transformed to a twist mode TW in the U-shaped radiator upper cross member 310. Due to this phenomenon, less vibration is generated in the U-shaped radiator upper cross member 310 as compared to that of vibrations generated in the conventional radiator upper cross member 112.
20 [0031] Fig. 5 illustrates a graph 500 pertaining to vibration performance of the engine mount portion 102 with the conventional radiator upper cross member 112 and the U-shaped radiator upper cross member 310. In an example, as seen in the graph 500, a difference of 7.3 dB at a frequency of 152 Hz is achieved. In other words, level of vibration transfer from the engine mount portion 102 to the floor
25 of the vehicle is reduced by 7.3 dB on employing the U-shaped radiator upper cross member 310.
[0032] Fig. 6 illustrates a graph 600 pertaining to tactile vibrations transferred to a floor of the vehicle from the engine mount portion 102 with the conventional radiator upper cross member 112 and the U-shaped radiator upper cross member
9

310. In an example, as seen in the graph 600, a 12-dB improvement in tactile vibrations experienced by the floor of the vehicle is achieved at 152 Hz.
[0033] Fig. 7 illustrates a graph 700 pertaining to drive-point frequency response function (FRF) comparison between the front chassis portion 100 and the front portion structure 300. The graph 700 indicates that amplitude level of vibration of the U-shaped radiator upper cross member 310 is reduced as compared to that of the conventional radiator upper cross member 112.
[0034] Further advantages of employing the U-shaped radiator upper cross member 310 include an increase in occupant comfort, weight saving due to non-increase of thickness or addition of mass dampers, increase in fuel efficiency, etc.
[0035] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:
A front portion structure (300) of a vehicle, the front portion structure (300) comprising:
a frame (302), which includes a hood lock member (304), two lateral vertical side members (306), and a lower cross member (308); and
a U-shaped radiator upper cross member (310) for supporting a radiator of the vehicle, the U-shaped radiator upper cross member (310) being coupled to an underside of the hood lock member (304),
wherein, the U-shaped radiator upper cross member (310) defines a plurality of arcuate portions (312) configured to be secured to the underside of the hood lock member (304), and an intermediate portion (314) provided substantially between the plurality of arcuate portions (312), the intermediate portion (314) being extending substantially in a forward (F) or a backward (B) direction of the vehicle.
The front portion structure (300) as claimed in claim 1, wherein length (LI) of the U-shaped radiator upper cross member (310) is less than length (L2) of the hood lock member (304).
The front portion structure (300) as claimed in claim 1, wherein a bracket (316) is provided between the hood lock member (304) and the intermediate portion (314) of the U-shaped radiator upper cross member (310).
The front portion structure (300) as claimed in claim 1, wherein decoupling of natural frequencies along with transformation of bending forces (BF) to twist mode (TW) of the U-shaped radiator upper cross member (310) and the hood lock member (304) is achieved in low frequency range based on the plurality of arcuate portions (312) and the intermediate portion (314).

The front portion structure (300) as claimed in claim 1, wherein the U-shaped radiator upper cross member (310) provides high dynamic stiffness to the frame (302).